function split(text, sep)
	local parts = {}
	local start = 0
	local from, to = text:find(sep)
	while from ~= nil do
		table.insert(parts, text:sub(start, from - 1))
		text = text:sub(to + 1)
		from, to = text:find(sep)
	end
	table.insert(parts, text)
	return parts
end

function sign(n)
	if n == 0 then return 0
	elseif n < 0 then return -1
	else return 1
	end
end